Unfortuantely this game doesn’t give points specifically for force preservation. That I suppose is the advantage gained by the A&A campaign games (currently Guadacanal) that link the minis to the board game. Then the points you get in a minis game are determined by the pieces on the larger strategic map. Alternatively look at the hospital discussion again.
There must be a better way for the minis commander to win without wasting his most valuable manpower.